This invention relates to novel couplers for use in hair coloring compositions comprising one or more oxidative hair coloring agents in combination with one or more oxidizing agents. The invention also relates to hair coloring compositions of these novel couplers and to coloring or dyeing of hair using compositions containing these couplers.
Coloration of hair is a procedure practiced from antiquity employing a variety of means. In modern times, the most extensively used method employed to color hair is to color hair by an oxidative dyeing process employing hair coloring systems utilizing one or more oxidative hair coloring agents in combination with one or more oxidizing agents.
Most commonly a peroxy oxidizing agent is used in combination with one or more oxidative hair coloring agents, generally small molecules capable of diffusing into hair and comprising one or more primary intermediates and one or more couplers. In this procedure, a peroxide material, such as hydrogen peroxide, is employed to activate the small molecules of primary intermediates so that they react with couplers to form larger sized compounds in the hair shaft to color the hair in a variety of shades and colors.
A wide variety of primary intermediates and couplers have been employed in such oxidative hair coloring systems and compositions. Among the primary intermediates employed there may be mentioned p-phenylenediamine, p-toluenediamine, p-aminophenol, 4-amino-3-methylphenol, and as couplers there may be mentioned resorcinol, 2-methylresorcinol, 3-aminophenol, and 5-amino-2-methylphenol. A majority of the shades have been produced with dyes based on p-phenylenediamine.
For providing an orange coloration to hair 2-methyl-5-aminophenol has been extensively used in combination with p-aminophenol as a primary intermediate. However, the resulting orange color on hair undergoes significant changes on exposure to light or shampooing. U.S. Pat. No. 4,065,255 and EP patent publications EP 634165 A1 and EP 667143 A1 suggest the use of 2-methyl-5-N-hydroxyethylaminophenol, 2-methyl-5-alkylaminophenol and 2-methyl-5-aminophenol as couplers. Therefore, there is a need for new orange couplers for use in oxidative hair dyeing compositions and systems.
This invention provides novel couplers of the formula (1) 
X is selected from halogen and R5SO4 where the halogen is preferably Cl, Br or I; R3 is selected from C1 to C2 alkyl and hydroxyethyl; and R, R1, R2 and R5 are each independently selected from C1 to C22 alkyl or C1 to C22 mono or dihydroxyalkyl. These novel couplers are used to provide coloration to hair in which there is good dye uptake by the hair and provides shades or colors which are stable over a relatively long period of time. The novel couplers provide for dyeing of hair that provides color or shades that possess good wash fastness and do not undergo the significant changes on exposure to light or shampooing as experienced with 2-methyl-5-aminophenol.
Preferred coupler compounds of this invention are those of formula (1) 
wherein is Cl, Br, I or R5SO4 where R5 is C1 to C3 alkyl; and R, R1 and R2 are each independently C1 to C3 alkyl, most preferably methyl.
Especially preferred couplers of this invention are the following compounds:
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium iodide;
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium chloride;
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium methyl sulfate;
{4-[3-hydroxy-4-hyrroxyethyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium chloride;
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-triethyl ammonium chloride;
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-tripropyl ammonium propyl sulfate;
{4-[3-hydroxy-4-ethyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium chloride; and
{4-[3-hydroxy-4-methyl-phenylamino)-methyl]-phenyl}-trimethyl ammonium bromide.
The compounds of formula (1) of this invention are readily prepared according to the following reaction sequence. 
In the reaction sequence a reductive amination of an aminophenol of formula (2) with a disubstituted benzaldehyde of formula (3) in the presence of a reducing agent such as sodium triacetoxyborohydride or sodium cyanoborohydride in 1% acetic acid in 1,2-dichloroethane produces a compound of formula (4). Reaction of the compound of formula (4) with the quaternization agent R-X in dimethylforamide (DMF) gives a compound of formula (1) of this invention where X, R, R1, R2 and R3 are as defined hereinbefore.